The "mobile-phonocardiogram", a new tool in the arrhythmia clinic

Development of a Low-Cost Wireless Phonocardiograph With a Bluetooth Headset under Resource-Limited Conditions

Commercially available digital stethoscopes can be used as a phonocardiograph to record heart sounds. However, procuring a costly digital stethoscope may not be possible under resource-limited conditions. A low-cost, wire connected, and mobile phone-assisted phonocardiograph has been reported previously. The aim of this study was to develop a low-cost and wireless phonocardiograph for resource-limited settings. A Bluetooth headset was dismantled to find its microphone. A stethoscope ear knob was cut to make a small bell and it was attached to the microphone. This modified Bluetooth headset was capable of recording sounds while connected to a mobile device with audio recording application. The modified Bluetooth headset, mobile phone, and audio recording software can serve as a wireless phonocardiograph (WiPCGh). Heart sounds were successfully recorded with the help of the newly developed WiPCGh. The audio files were shared with a personal computer (PC) via Bluetooth. The wave form was analyzed in a PC-based audio editing application. First and second heart sounds with systolic and diastolic murmur were identified. WiPCGh can be utilized in recording heart sounds for academic and telemedicine purposes. However, the capability of WiPCGh in the diagnosis of cardiac diseases is yet to be explored in future studies.

Development of a Smartphone App for Visualizing Heart Sounds and Murmurs

BACKGROUND

Auscultation is one of the basic techniques for the diagnosis of heart disease. However, the interpretation of heart sounds and murmurs is a highly subjective and difficult skill.

OBJECTIVES

To assist the auscultation skill at the bedside, a handy phonocardiogram was developed using a smartphone (Samsung Galaxy J, Android OS 4.4.2) and an external microphone attached to a stethoscope.

METHODS AND RESULTS

The Android app used Java classes, "AudioRecord," "AudioTrack," and "View," that recorded sounds, replayed sounds, and plotted sound waves, respectively. Sound waves were visualized in real-time, simultaneously replayed on the smartphone, and saved to WAV files. To confirm the availability of the app, 26 kinds of heart sounds and murmurs sounded on a human patient simulator were recorded using three different methods: a bell-type stethoscope, a diaphragm-type stethoscope, and a direct external microphone without a stethoscope. The recorded waveforms were subjectively confirmed and were found to be similar to the reference waveforms.

CONCLUSIONS

The real-time visualization of the sound waves on the smartphone may help novices to readily recognize and learn to distinguish the various heart sounds and murmurs in real-time.